PYONGYANG, North Korea (AP) -- North Korea's young leader Kim Jong Un on Wednesday made his second speech at a major public event since taking power in December, addressing a children's rally aimed at winning a new generation's support.

About 20,000 young people gathered at Pyongyang's Kim Il Sung Stadium for a speech that capped an unprecedented six-day children's festival. The celebrations took place two days after North Korea's military threatened to fire at South Korean media companies unless they apologized for criticisms of the festivities, including a Channel A report comparing the event to Hitler Youth rallies during Germany's Nazi era.

North Korea typically holds mass events for landmark anniversaries such as the leaders' birthdays and the founding of the Workers' Party or military. It is the first time such extensive celebrations have been organized for the founding of the Korean Children's Union, the first political organization young North Koreans join.

North Korean children are taught from an early age to be loyal to the Kim family, with education about the childhoods and accomplishments of founder Kim Il Sung and late leader Kim Jong Il beginning in kindergarten. Seeing and hearing their new leader in person is likely to reinforce a sense of paternal awe among the children, who are raised to refer to the leaders as "father."

Kim walked into the stadium, accompanied by two children, to the cheers of the young delegates to the Korean Children's Union. He was wearing the red scarf of the political organization around his neck as he smiled and laughed with them.

"By mingling with kids, Kim Jong Un is showing that he is a leader who can interact with the public," said Ahn Chan-il, a political scientist who heads the World Institute for North Korea Studies in Seoul, South Korea. "He understands that one of the keys to winning back the respect of the people is by starting with the young generation."

By speaking publicly twice in his six months as leader, Kim already is distinguishing himself from his father. Kim Jong Il, who died in December, addressed the public only once, two years before he succeeded father Kim Il Sung.

Kim told the children, who were dispatched to Pyongyang for the gathering by plane, train and bus from across the nation, that they were the future masters of "a most powerful country where every home will be full of laughter and everybody lives in harmony."

In the lobby coffee shop of Pyongyang's Koryo Hotel, waitresses in bright red suits gathered around a big flat-screen TV to watch the speech. Throngs of children dressed in their school uniforms could be seen with their families in parks and plazas.

June 6 marks the 66th anniversary of the founding of the Korean Children's Union, which students join at age 7 until they graduate at age 13 to the Kim Il Sung Socialist Youth League.

South Korean media have called the festivities "a political show." The criticism prompted the North Korean military to warn it would fire at South Korean media outlets if Seoul refused to apologize for orchestrating what North Korea called a "vicious smear campaign."

The North's statement was the latest in a series of threats aimed at South Korea's president and news agencies following the death of Kim Jong Il, which Pyongyang feels was not respectfully acknowledged by Seoul.

The Korean peninsula remains in a state of war because the 1950-53 conflict ended with an armistice, not a peace treaty.